Recently in my 38gal brackish tank, I've had a couple of saddening deaths with my black mollies. Could anyone help me figure out the reason for these deaths so I can save my remaining three mollies? So far, the deaths have been identical to each other. What happens to my mollies is they'll start to experience what looks like losing scales around the face, so their faces will look grayer instead of jet black. Then I'll see that they're missing huge chunks of their tails, as if they were torn off. It doesn't look like fin rot, it looks more like an injury. And two days after that, I'll find them dead. This has happened to two of my mollies so far, one after the other. Does anyone know what could be causing it? Thank you.